In-building wireless networks have become commonplace. Such networks typically employ multiple antennas distributed around the interior of the building and in a manner that strives to maximize coverage while minimizing the number of antennas. Due to the proliferation of different types of wireless communication systems (e.g., cellular, PCS, and WLAN) and the different frequency bands in which these systems operate, many of the antennas used in in-building wireless networks are designed for broadband operation so as to be able to accommodate as many of the different wireless communication systems as are likely to be used within the building as possible. Further, the antennas employed typically are capable of duplex operation (i.e., can be used to send a wireless signal and receive a wireless signal) and have radiation patterns that endeavor to maximize the coverage within a particular volume of the building.
Many antennas used in in-building wireless networks are associated with an interior building structure (such as a wall or ceiling) that has: (a) a room-side surface which defines at least a portion of the room-space within which the device(s) with which the antenna is to communicate are expected to be located and (b) a plenum-side surface that at least partially defines a hollow and enclosed plenum-space that accommodates an electrical cable (e.g., coaxial cable) that is used to transfer electrical signals to and/or from the antenna. To support such antennas in a desired orientation and location, some form of mounting structure is employed.
Generally, the known antennas and mounting structures that have evolved for use with in-building wireless networks can be categorized into three types. In the first type, the mounting structure engages the interior building structure and supports the antenna such that the antenna extends away from the room-side surface of the structure and into the room-space. Many of this type of in-building antenna and mounting structure employ a radome to cover the antenna and enhance the aesthetic appeal of the antenna and mounting structure. An example of such an in-building antenna and mounting structure can be found in U.S. Pat. No. 6,642,899. The second type of in-building antenna and mounting structure disposes the antenna and the mounting structure entirely within the plenum-space so that neither the antenna nor the mounting structure is visible to anyone in the room-space. An example of this type of antenna and mounting structure can be found in U.S. Pat. No. 7,039,366. The third type of in-building antenna and mounting structure embeds the radiator of the antenna within the interior building structure and embeds or mounts the remainder of the antenna either in the interior building structure or on the plenum-side of the interior building structure. An example of this type of antenna is shown in U.S. Pat. No. 6,563,465, which discloses a ceiling tile antenna with the radiator of the antenna embedded within a ceiling tile, a ground plane for the antenna located on the plenum-side of the ceiling tile, and a portion of the ceiling tile forming the dielectric that extends between the radiator and the ground plane.